Washington (CNN) -- Israel and the Palestinian Authority have agreed to hold direct peace talks beginning September 2 in Washington -- the first such talks since 2008.

The talks, also involving other regional and international players, are intended to resolve all "final status" issues for a Middle East peace agreement, "which we believe can be done in one year," Secretary of State Hillary Clinton said.

"These negotiations should take place without preconditions and be characterized by good faith and a commitment to their success, which will bring a better future to all of the people of the region," Clinton said.

Shortly after the announcement, Israeli Prime Minister Benjamin Netanyahu said he welcomed the invitation for direct talks without preconditions.

The executive committee of the Palestinian Liberation Organization said it, too, would participate, though chief Palestinian negotiator Saeb Erakat told CNN that Israel must extend its moratorium on settlements that is due to expire September 26.

"The nonextension of this moratorium in settlements will mean we will not have negotiations. It's as simple as this," he said.

About the goal of resolving long-standing issues, he said, "I think it's doable."

But Israeli government spokesman Mark Regev said the Palestinians must offer something, too. "We want to make sure there are ironclad agreements to make sure there will be peace and security, because you can't have one without the other."

Hamas, the anti-Israel group that runs Gaza, rejected the talks, though the group had not been invited to join them. Hamas spokesman Sami Abu Zuhri said that negotiations until now "did not achieve anything," and that "these negotiations will not be accepted by the Palestinian people because it is a new trap for the Palestinians."

Former Sen. George Mitchell said the invitation had been made to Palestinian Authority President Mahmoud Abbas, who is considered the leader of the Palestinians, and not to Hamas.

Both Netanyahu and Abbas are fully committed to direct negotiations for the benefit of their people, said President Barack Obama's special envoy to the talks.

"I believe the two leaders ... are sincere and serious and believe it can be done and will do everything possible to see that it is done," Mitchell said. He said the goal of the negotiations was to end the Middle East conflict "for all time," with establishment of a "viable, independent" Palestinian state next to Israel.

The announcement prompted skepticism about whether yet another attempt at peace talks can resolve the decades-long conflict that has shaped regional and international politics and security.

Both Clinton and Mitchell warned that obstacles abound to a final agreement. Clinton predicted that "enemies of peace" would try to derail the talks, while Mitchell acknowledged that "there remains a mistrust between the parties" based on "a residue of hostility developed over many decades of conflict."

"We don't expect all those differences to disappear when talks begin," Mitchell said, adding: "Past efforts at peace that did not succeed cannot deter us from trying again, because the cause is noble and just and right for all concerned."

A veteran of peace talks in Northern Ireland, Mitchell said the Middle East talks will require "patience, persistence, a willingness to go back again and again, to not take the first 'no' as a final 'no,' to not take the 50th 'no' as the final 'no' or the 100th 'no.' "

The talks would be the first direct negotiations between the parties since December 2008, when the process broke down over Israel's three-week offensive in Gaza. Mitchell has been engaged in "proximity" talks with the two sides in recent months to lead up to the possibility of resuming direct talks.

Obama has also invited Jordan, Egypt and members of the Middle East Quartet -- the United States, Russia, the United Nations and the European Union -- to the table, Clinton and Mitchell said.

In a statement Friday, the quartet underscored its full commitment to the talks, calling on "both sides to observe calm and restraint, and to refrain from provocative actions and inflammatory rhetoric."

Quartet representative Tony Blair, who also plans to attend, welcomed the announcement.

"I and my team will also continue to work with both the Israelis and Palestinians to develop the bottom-up process in order to build up the institutions and economy of the West Bank and Gaza and improve the daily lives of Palestinians, in support of the political negotiations," the former British prime minister said in a statement. "With the resumption of talks, I hope that more can now be done to accelerate the process of change on the ground."

A senior diplomatic official told CNN that U.S. engagement in the effort had led to traction in the last few months and that the talks were urged to begin before a moratorium on Jewish settlements ends and the U.N. General Assembly adjourns.

Oscar Fernandez-Taranco, U.N. assistant secretary-general for political affairs, called on Israel this week to continue the moratorium on all settlement activity -- including in East Jerusalem -- beyond September 26.

"We are nearing a turning point in the efforts to promote direct negotiations between Israel and the Palestinians," Fernandez-Taranco told the Security Council.

Clinton and Mitchell urged Israelis and Palestinians to avoid taking any action or making any comments that would harm the atmosphere for launching peace talks.

"We think that these talks should be conducted in a positive atmosphere in which the parties refrain from taking any steps that are not conducive to making progress in the discussions," Mitchell said.